Generally, the size of shoes is represented by the length from the heels to the fingertips. However, the shapes of a human foot, for example, not only the foot length but also the height of the instep, the foot breadth, and so on, are of various types depending on individuals. When an attempt to make shoes corresponding to the shape of the foot of each person is made, it is necessary to measure the three-dimensional shape of the foot. In the present condition, however, the sizes of limited portions, for example, the foot length, the foot breadth, and the perimeter of the foot are only measured using a measure.
On the other hand, an active stereo type shape measuring device for irradiating an object to be measured with spot light or slit light and restoring a three-dimensional shape from the position of a light image observed on a surface of the object to be measured has been known. The shape measuring device is for scanning the spot light or the slit light using a rotating mirror in order to measure the shape of the surface of the object to be measured. In a magazine “Measurement and Control” (1999 Vol. 38 No. 4 P285-P288), a system for measuring the shape of a foot using such a shape measuring device is described.
In the system, one shape measuring device can measure only the shape of a portion observed from the device and cannot measure the shape of a concealed portion on the opposite side of the observed portion, for example. Accordingly, 12 shape measuring devices are disposed around the foot, and the results of the measurement by the 12 shape measuring devices are synthesized on a computer, to measure the shape of the whole foot.
In the system, however, the plurality of shape measuring devices are arranged around the foot, so that the system increases in size and in cost. Moreover, it is difficult to synthesize the results of the measurement by the plurality of shape measuring devices with high precision.
Contrary to this, the applicant of the present invention has already developed a shape measuring device for making measurement by holding a compact measuring head in a person's hand and moving the measuring head around an object to be measured (see JP-A-2000-39310). In the shape measuring device, a plurality of markers attached to the measuring head are imaged from above by two cameras to measure the position and the direction of the measuring head.
In this proposal, it is necessary to image the whole of the moving range of the measuring head from the two cameras positioned above. Accordingly, the two cameras are set up at positions spaced apart from the object to be measured in order to widen a field of view common to the cameras, resulting in the necessity of a large setup space. Further, when a part of the marker attached to the measuring head is depart from the field of view common to the two cameras and is concealed by the hand of a measuring person who holds the object to be measured and the measuring head, the shape of the object to be measured cannot be measured. Accordingly, it has been tedious for the measuring person to pay attention to the marker attached to the measuring head such that the marker is always imaged by the two cameras.
An object of the present invention is to provide a shape measuring device capable of measuring the shape of an object to be measured without a user being conscious of a field of view of a camera to improve the feeling of use.
Another object of the present invention is to provide a shape measuring device capable of measuring a suitable three-dimensional shape in a small number of procedures for measurement.